Hi Gilla999
As far as I understand it, this is not any particular hormonal condition as such, but a normal part of that process we women go through called menopause! There is no actual standard despite the different stages of reproductive ageing having been characterised as per that link I gave ie each woman's experience will be subtly ( or not so subtly) different....
In fact in that link, towards the end it says this:
"The course of reproductive aging in women with POI/premature ovarian failure seems to be considerably more variable than that of women with normal reproductive aging.
Not only are there several potential etiologies but also a substantial proportion of women have spontaneous resumption of menstrual function once the diagnosis has been confirmed, including ovulation and successful spontaneous pregnancy.76 Additional research is needed to better document the process of ovarian aging in these women and whether the course of ovarian aging differs by etiology of POI. Studies of reproductive aging in POI are considered to be a research priority." (my bold)
Although you say you have been ovulating the whole time, the shortened cycles do indicate you were nearing peri-menopause....
"But I can't seem to find any kind of hormone condition that would cause that. It's very strange and makes me feel a bit isolated and confused in my experience. Perhaps I will never know or understand why my hormones have wrecked my life over the last four years and I need to come to terms with that "
I'm sorry that you feel your hormones have wrecked four years of your life, but yes I think the exact mechanism by which our individual bodies go through the myriad of hormonal changes as we approach menopause, may remain a mystery - though in principle it is expected. In your case, unless premature menopause is in the family, then this is the question - why did your body decide to approach menopause - or rather enter the late reproductive stage - at a relatively young age?
I think you will torment yourself if you continue to dwell on this, and as you say, accepting that your body did start to go through changes then, is the way forward. The most important thing is to focus now on what you need to do to feel better. You said you used Zoely - but that is lower oestrogen - Qlaira is variable but much higher - so perhaps it is worth trying that if you want a bit more stability and want to prevent ovulation. However if you are feeling well on your current regime then keep on with it, but I really suggest stop getting hung up on oestrogen levels and having them measured - it doesn't really matter unless you feel that because you are ovulating and levels are high, that you don't need HRT? Provided the dose is not exceptionally high then it is unlikely to be too high, if you feel well?
I don't think I've helped much here as I don't have an answers, but hopefully a little.
Wishing you well - and just try to relax
Hurdity x